Signal system



Aug. 17, 1948. P. SITZER SIGNAL SYSTEM Filed Feb. 5, 1944 VULTAG E SUPPLY BIG/ML LAMPS VOLTA GE 5 UPQPLY IMML TIA/5 M4 TEE/IL 43 6 TO RELAY 20 2'0 T0 SIGNAL 2 INVENTOR BY PHIL /P 5/ 725/? TO SIGNAL AND RELAY 78M, g M; k -I1;

A TTORNEYU Patented Aug. 17, 1948 SIGNAL SYSTEM Philip Sol Lamp Works, Inc.,

tion of Delaware Sitzer, Irvington, N. J assignor to Tung- Newark, N. J a corpora- Application February 3, 1944, Serial No. 520,859

8 Claims.

My present invention relates to electrical circuits of the type employed for alternately energizing electrical devices, as for example for lamps that are to be alternately flashed. More specifically, the invention comprises an improved and relatively simple circuit of this general type which provides a period of quiescence between the flashing of one lamp or bank of lamps and that of another lamp or bank while omitting such period between the extinguishment of the latter lamp or bank and the lighting of the former. The various fields of application of the new circuit, as for example in signalling systems, or in advertising signs, will be apparent to those skilled in the art.

For an understanding of the invention, reference may be had to the accompanying drawings, of which:

Fig. 1 is a diagrammatic cincuit drawing illustrating one embodiment of the invention;

Fig. 2 is a diagrammatic circuit drawing illustrating another embodiment of the invention;

Figs. 3, 4 and 5 are-diagrammatic views explanatory of the action of the triple switch of Fig. 2; and

Fig. 6 is a circuit drawing illustrating a flasher means which may be used in Figs. 1 and 2.

The invention will first be described with reference to the relatively simple circuit of Fig. 1., The circuit of Fig. 1 is arranged to alternately flash lamps 2 and 4 with a period of quiescence following the extinguishment of lamp 2 when a source of voltage is connected to terminals 6; A switch arm 3, connected to one terminal 6, is alternated between fixed contacts 10 and 12 by any suitable mechanism, such as an alternate flasher, or magnetic relay operated by a flasher. The lamp 2 is connected between one terminal 6 o! the source 25. As coil 22 of relay is connected across lamp 23, some current will flow through the coil but, because of the resistance characteristic of the tungsten filament of lamp 26, suflicient voltage is not attained across the coil 22 for attraction of the armature I8 until the filament of lamp 26 heats up. When sufficient voltage is impressed across coil 22, armature I8 is moved into engagement with contact IE to close the circuit of lamp 4. Thus between the extinguishment of lamp 2 and the energization of lamp 4 there is a period of quiescence or eclipse corresponding to the time required for the heating of the filament of lamp 26. On the otherhand, when switch arm 8 disengages contact l2 and reengages contact I0, lamp 4 is extinguished and lamp 2 immediately energized. At I4 is indicated in dotted lines a suitable casing for the switch mechanism 8, l0, l2.

The circuit of Fig. 2, like that of Fig. 1, is arranged to flash lamps 2 and 4 alternately under control of the flasher operated switch arm 8;

' lamp 2 being lighted when :arm 8 engages contact and fixed contact [0 and hence is energized when arm 8 engages contact l0. Lamp 4 is connected directly to one terminal 6 of the source and to a iixed contact l6 engageable by an armature l8 of a relay 2!); the armature I8 being connected to the other terminal 6 of the source. The winding 22 of relay 20 is connected at one end with a terminal 6 and at the other end, througha variable resistor 24, with fixed contact l2. A positive temperature coeiiicient resistance such as tungsten filament lamp 2G is connected in parallel with the coil 22.

With the above described circuit, when the switch arm 8 disengages contact In and engages contact 12 lamp 2 is extinguishedand current flows through resistor 24 and the filament of lamp I0, and both lamps 2 and 4 being extinguished for a short period following engagement of arm 8 with contact l2 prior to the lighting of lamp 4. The relay 20a of Fig. 2 includes a triple switch having the movable elements 28, 30 and 32 of which elements 28 and 30 are nomnally in circuit closing position and element 32 is normally in open circuit position. The triple switch is so arranged that upon energization of the coil 22d of the relay, switch element 32 closes its circuit before switch elements 28 and 30 open their respective circuits. The operation of the triple switch is illustrated diagrammatically in Figs. 3, 4 and 5 to which reference may now be had. Fig. 3 shows the normal position of the switch elements when the coil of relay 20a is not energized. A link 34 of insulating material is connected with a bell crank lever of which the armature 36 of the relay forms one arm and the movable elements 28, 30 and 32 are connected with the link 34 for movement therewith. Fixed contacts 38, I

40 and 42 for respective engagement with the arms 28, 30 and 32 are yieldingly mounted adjacent the arms. In the normal position shown in Fig. 3 arms 28 and 30 engage contacts 38 and 40, respectively, whereas arm 32 is out of engagement with contact 42. Upon energization of the relay 20a, armature 36 is attracted and lever 34 moved through the position illustrated in Fig. 4, wherein all arms of the switch are in circuit closing position, to that illustrated in Fig. 5 when- 1 other resistance having a. suitable ever arm 32 engages contact 42 .and the circuit controlled by arm 28 is open and arm 88 engages a contact 78 for closure of the circuit of lamps 43.

As shown in Fig. 2 switch arm 28 in the normal closed circuit position connects the winding 22a of relay 28a across the tungsten filament lamp 26a and switch arm 38 in the normal position closes the circuit from contact M of flasher it through resistance 24a. to lamp 26a and switch arm 28. Switch arm 88 in the normal position prevents the application of line voltage to the lamp 4.

.Inthe operated position arm 38 closes the cir- I cult to lamp 4. Arm 82. in the operated position,

provides a holding circuit for coil 2241 through a resistor 44.

The operation of the circuit of Fig. 2, insofar as the energization of lamps 2 and t are concerned. is the same as described in connection with the circuit of Fig. 1. That is, when arm 8 of theflasher engages contact i8, lamp 2 is immediately energized, whereas upon engagement of contact 02 by arm 8 there is a period of quiescence, corresponding to the heating up of the filament of lamp 26a, before energization of lamp 4. However, due to the provision of the triple switch and the sequence of operation of the arms thereof as shown in Figs. 3 to 5, lamp 28a is energized only during the period of quiescence following energization of lamp 2; the circuit of lamp 26a being broken by arm 38 after the holding circuit for the coil 22a is closed through arm 82 and contact 42.. The opening of switch arm 28 prevents energization of lamp 26a through the holding cincuit of coil 22a.

From the above description of the circuits of Figs. 1 and 2, it will be apparent that the latter circuit has certain advantages over the former, among,which are the following:

In Fig.2 once the relay has operated, after the time delay period, full .holding current can be supplied to the coil. In the circuit of Fig. 1, it may not always be possible to obtain full holding current for the coil because of the necessity for proportioning the value'of the resistance 24 to the resistance of the filament of lamp 26 for the desired time delay. 7

In Fig. 2 the filament of lamp 26a is never heated more than is necessary and hence has a longer cooling off period which results in more efiective use of its time-delay characteristics, and also in a. saving of power.

The invention has now been described in connection with two embodiments thereof. In each embodiment the devices to be flashed have been indicated for convenience as the two lamps 2 and 4. It will be readily apparent that the invention is equally applicable whether thedevices to be alternately energized are single lamps, banks of lamps, audible signals or other electrical devices.

Also, in each embodiment of the invention the element controlling the time delay has been described as tungsten filament. Obviously any positive resistance-temperature coeflicient could'be substituted therefor. Also various other changes could be made in the described circuits without departing from the spirit of the invention as defined in the appended claims.

The preferred form of flasher for use with the circuits of Figs. 1 and 2 is illustrated inFig. 6 and comprises a device, indicated at '46, arranged for intermittently opening and closing the circuit of a @011 4a controlling the switch arm 8. Device 46 includes a vane 58 secured at its ends to a frame 52 and constrained into the curved position shown in full lines in Fig. 6 by the tension, when cold, of a wire 5!. A heater 58 for the wire 5| is connected at one end to one terminal of the source 6 and at its other end to the vane 58. A fixed contact 58 connected to the other terminal of the source 8 completes the circuit of the heater 58, when the vane 58 is in the full line position, by engagement with a contact 68 carried by the vane. Fixed contact 58, when in engagement with contact, also closes the circuit for coil 48 controlling switch arm 8; one end of the coil 48 being connected to one terminal of the source 6 and the other end being connected to the vane 58. When relay coil 48 is energized, switch arm 8 is attracted into engagement with contact l2 for energization of lamp' 4 following the period of quiescence or black-out. When the wire 5| expands under the influence of the heat from the heater 56, the constraint on vane 58 is removed and the vane snaps to the open circuit position shown in dotted lines in Fig. 6. The consequent deenergization of coil 48 causes arm 8 to disengage contact i2 and engage contact Ill, whereupon lamp 4 is extinguished and lamp 2 energized. Upon the opening of the circuit of the heater 56, wire 5! cools and its tension increases. When the tension of thewire increases sufficiently, vane 58 snaps back to circuit closing position, coil 48 and heater 55 are energized and switch arm 8 reengages contact i2.

The illustration of the flashing means in Fig. 8 is purposely diagrammatic and the details of structure are omitted for convenience. For example, it is understood that when the coil 48 is deenergized the arm 8 is automaticall moved to a position to close the circuit at 60, as by any suitable means such as being spring biased to that position by a spring 6i. Thefrequency of operation of the flasher and the relative lengths of the on-and-oflf periods may be varied within the signal ,4 may be white.

limits at will, as for example by adjustment-of the tension of wire 5|, by varying the physical constants of the wire or vane, by change of the position of the heater coil 56 with reference to it, 'by varying the amplitude of movement of the contacts 60, etc., as is well understood in flashers of this type. The period of black-out, eclipse, or quiescence between the operation of the signal 2 and the signal 4, as indicated above, may be adjusted or varied by the relative proportioning of the constants of the elements 22, 22a, the elements 24, 24a, the elements 26, 26a, etc. Thus with the flasher means shown in Fig. 6 and the circuits of Figs. 1 and 2, the periods of energization of the lamps 2 and 4 and the black-out period may be varied to obtain the exact periods desired in practice. For example, as applied to the flashing signals .of aeroplanes, the flasher and circuit may be so adjusted that the periods of energlzation of each of the lamps 2 and 4 is .625 second and the period of black-out or quiescence following the lighting of lamp 2 and preceding the energization of lamp 4 is .25 second. This is found in practice to be particularly advantageous where the signal 2 is a, red signal while The time it requires the vane 58 to snap from open to closed position of the contacts 58 and 60 and vice versa is for practical purposes so small as to be instantaneous, and the period between the extinguishment of lamp 4 and the lighting of lamp 2 is very small as compared with the period of eclipse following the extinguishment of the signal 2, as for example this period may not be greater than .02 second. With the above indicated lighting and eclipse periods the flasher I6 is so adjusted that the closed circuit position of the coil 48 is of relatively longer duration than the open circuit position, the diflerence being roughly equal to the eclipse period.

I claim:

1. The combinationwith a source of electrical energy and a switch arm alternated between fixed contacts of a circuit comprising a pair of electrical devices, circuit connections for connecting one of said devices across said source when said switch arm engages one of said contacts, circuit connections for connecting the other of said devices across said source when said switch arm engages the other of said contacts and means associated with said last mentioned connections for providing a period of delay between the engagement of said switch arm with said other contact and the energization of said other device.

2. The combination with'a source of electrical energy and a switch arm alternated between fixed contacts of a circuit comprising a pair of electrical devices, circuit connections for connecting one of said devices across said source when said switch arm engages one of said contacts, circuit 'connections for connecting the other of said devices across said source when said switch arm engages the other of said contacts and means associated with said last mentioned connections for providing a period of delay between the engagement of said switch arm with said other contact and the energization of said other device, said last mentioned means including a solenoid connected to said other contact, a switch controlled by said solenoid so as to close when full current is supplied to the solenoid, said last mentioned switch being in circuit with said second device, and means connected with said solenoid for delaying the application of full current thereto.

3. In a circuit of the type described, the combination comprising a solenoid, a switch controlled thereby so as to be closed when the current through the solenoid exceeds a predetermined value, a device connected to said switch for energization when said switch is closed, a switch having a single pole and two fixed contacts, said solenoid being connected to one of said contacts for energization when the pole engages said contact, a second device connected to the other fixed contact for energization when the pole engages said other fixed contact, a resistor connected in series with said solenoid, and an element connected in parallel with said solenoid for providing a period of delay between the engagement of the pole with the first fixed contact and the attainment of the predetermined magnitude of current through the solenoid whereby when said pole is reciprocated back and forth between the fixed contacts there is a period of quiescence following the deenergization of the last mentioned device before the first mentioned device is energized. I

contacts there is a period of quiescence following 4. In a circuit of the type described, the combination comprising a solenoid, a switch controlled thereby so as to be closed when the current through the solenoid exceeds a predetermined value, a device connected to said switch for energization when said switch is closed, a" switch having a single pole and two fixed contacts, said solenoid being connected to one of said contacts for energization when the pole engages said conthe deenergization of the last mentioned device before the first mentioned device is energized, a holding circuitv for said solenoid and means controlled by said solenoid for opening the circuit of said element after closure of said first mentioned switch.

5. In a circuit of the type described, the combination comprising a solenoid, aswitch controlled thereby so as to be closed when the current through the solenoid exceeds a predetermined value, a device connected to said switch for energization when said switch is closed, a switch having a single pole and two fixed contacts, said solenoid being connected to one of said contacts for energization when the pole engages said contact, a second device connected to the other fixed contact for energization when the pole engages said other fixed contact, a resistor connected in series with said solenoid, an element connected in parallel with said solenoid for providing a period of delay between the engagement of the pole with the first fixed contact and the attainment of the predetermined magnitude of current through the solenoid whereby when said pole is reciprocated back and forth between the fixed contacts there is a period of quiescence following the deenergization of the last mentioned device before the first mentioned device is energized, said element being a tungsten filament lamp whereby the period of delay corresponds to the time required for the filament to heat up to operating temperature,

6. In a circuit of the type described, a relay including a coil and an armature, three electrically independent switches connected with said armature for operation upon attraction of the armature by the coil, one of said switches being normally open and the other switches being normally closed, the connections between said armature and said switches being such that movement of said armature to attracted position first closes said normally open switch and then opens said normally closed switches, a supply circuit for said coil, including a resistor and both of said normally closed switches, a switch controlling said circuit, a flasher for operating said last mentioned switch, an element having a positive resistancetemperature coefficient connected across said coil and one of said normally closed switches for providing a period of delay between closure of the supply circuit by the flasher operated switch and attraction of the armature, a holding circuit for said coil, and a pair of devices to be alternately mally open and the other switches being normally closed, the connections between said armature and said switches being such that movement of said armature to attracted position first closes said normally open switch and then opens said normally closed switches, a supply circuit for said coil, including a resistor and both of said normally closed switches, a switch controlling said circuit, a flasher for operating said last mentioned switch, an element having a positive resistancetemperature coefilcient connected across said coil and one of said normally closed switches for provicling a period of delay between closure of the supply'clrcuit by the flasher operated switch and attraction of the armature, a holding circuit for said coil, and a pair of devices to be alternately energized, one of said devices Ming connected to said flasher operated switch for energization when the supply circuit of said relay is open and theother of said devices being connected to one of said relay operated switches for energization upon movement of the armature to attracted position, said element being a tungsten filament lamp whereby energization of said other device, following deenergiz'ation of the device connected to the ilasher operated switch is delayed for a period corresponding to the heating-up period of the filament.

8. In a circuit 01' the type described, the com bination comprising a solenoid, a switch controlled thereby so as to be closed when the current through the solenoid exceeds a predetermined value, a device connected to said switch for energization when said switch is closed, a switch having a single pole and two fixed contacts, said solenoid being connected to one of said contacts for energization when the pole engages said contact, a second device connected to the other fixed contact for energization when the pole engages said other fixed contact, a resistor connected in series with said solenoid, an element connected in parallel with said solenoid for providing a period of delay between the engagement of the pole with the first fixed contact and the attain- Number ment of the predetermined magnitude of current through the solenoid whereby when said pole is reciprocated back and forth between the'fixed contacts there is a period 01' quiescence followin the deenergization of the last mentioned device before the first mentioned device is energized, a flasher device for reciprocating said pole between'the fixed contacts, said flasher devic including a vane fixed at its ends and normally assuming one position, a thermal responsive element for constraining said vane into a second position when the element is cold, a coil for operating said pole energized when said vane is in one position and means for heating said thermal element only when the vane is in its constrained position whereby the pole is reciprocated in accordance with the movement of said vane from one position to the other.

PHILIP SITZER.

REFERENCES (IITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date De Barry June 2, 1908 Number FOREIGN PATENTS Country Date Great Britain Oct. 23, 1940 Great Britain Dec. 8, 1943 Alinquist June 5, 1928 p 

